The invention relates to the automotive industry and more particularly to reducing the pollution caused by internal combustion engines, in particular diesel engines.
The exhaust lines of diesel engine motor vehicles of recent design are equipped with various devices for treating pollutants produced by combustion of fuel in the engine.
A first of those devices oxidizes the exhaust gases by passing them over an oxidation catalyst.
A second of those devices, generally disposed immediately downstream of the previous device, is a particle filter on which particles (known as soot) produced by combustion are deposited. This soot must be burned off periodically, in particular by increasing the temperature of the particle filter or the exhaust gases, to prevent the filter from becoming clogged and to restore its original performance (which operation is known as regeneration).
To assist this combustion of the soot, a suitable device may be used to add to the fuel an additive such as ceria and/or iron oxide that mixes with the soot and reduces its combustion temperature. The particle filter must be cleaned to remove the additive and various unburned residues approximately every 80,000 kilometers (km) or 120,000 km, for example.
Executing these oxidation and filtration functions in separate devices leads to very bulky exhaust line designs or to having to carry out thorough cleaning of the particle filter at intervals that might be deemed too frequent.